% \iffalse meta-comment
%
% Copyright 2025
% The LaTeX Project and any individual authors listed elsewhere
% in this file.
%
% This file is part of the LaTeX base system.
% -——————————————
%
% It may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3c
% of this license or (at your option) any later version.
% The latest version of this license is in
%    https://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions of LaTeX
% version 2008 or later.
%
% This file has the LPPL maintenance status "maintained".
%
% The list of all files belonging to the LaTeX base distribution is
% given in the file `manifest.txt'. See also `legal.txt' for additional
% information.
%
% The list of derived (unpacked) files belonging to the distribution
% and covered by LPPL is defined by the unpacking scripts (with
% extension .ins) which are part of the distribution.
%
% \fi
% Filename: ltnews43.tex
%
% This is issue 43 of LaTeX News.

\NeedsTeXFormat{LaTeX2e}[2020-02-02]

\documentclass{ltnews}

%% Maybe needed only for Chris' inadequate system:
\providecommand\Dash {\unskip \textemdash}

%% NOTE: Chris' preferred hyphens!
%% \showhyphens{parameters}
%% \hyphenation{because}

\usepackage[T1]{fontenc}

\usepackage{lmodern,url,hologo}

\usepackage{csquotes}
\usepackage{multicol}
\usepackage{color}

\usepackage{amsmath}

\providecommand\hook[1]{\texttt{#1}}

\providecommand\meta[1]{$\langle$\textrm{\itshape#1}$\rangle$}
\providecommand\option[1]{\texttt{#1}}
\providecommand\env[1]{\texttt{#1}}
\providecommand\Arg[1]{\texttt\{\meta{#1}\texttt\}}


\providecommand\eTeX{\hologo{eTeX}}
\providecommand\XeTeX{\hologo{XeTeX}}
\providecommand\LuaTeX{\hologo{LuaTeX}}
\providecommand\pdfTeX{\hologo{pdfTeX}}
\providecommand\MiKTeX{\hologo{MiKTeX}}
\providecommand\CTAN{\textsc{ctan}}
\providecommand\TL{\TeX\,Live}

\providecommand\githubissue[2][]{\ifhmode\unskip\fi
     \quad\penalty500\strut\nobreak\hfill
     \mbox{\small\slshape(%
       \href{https://github.com/latex3/latex2e/issues/\getfirstgithubissue#2 \relax}%
          	    {github issue#1 #2}%
           )}%
     \par\smallskip}

% simple solution right now (just link to the first issue if there are more)
\def\getfirstgithubissue#1 #2\relax{#1}

% issues from the tagging-project:

\providecommand\taggingissue[2][]{\ifhmode\unskip\fi
     \quad\penalty500\strut\nobreak\hfill
     \mbox{\small\slshape(%
       \href{https://github.com/latex3/tagging-project/issues/\getfirstgithubissue#2 \relax}%
          	    {tagging-project issue#1 #2}%
           )}%
     \par\smallskip}

\providecommand\sxissue[1]{\ifhmode\unskip
     \else
       % githubissue preceding
       \vskip-\smallskipamount
       \vskip-\parskip
     \fi
     \quad\penalty500\strut\nobreak\hfill
     \mbox{\small\slshape(\url{https://tex.stackexchange.com/#1})}\par}

\providecommand\gnatsissue[2]{\ifhmode\unskip\fi
     \quad\penalty500\strut\nobreak\hfill
     \mbox{\small\slshape(%
       \href{https://www.latex-project.org/cgi-bin/ltxbugs2html?pr=#1\%2F\getfirstgithubissue#2 \relax}%
          	    {gnats issue #1/#2}%
           )}%
     \par}

\let\cls\pkg
\providecommand\env[1]{\texttt{#1}}
\providecommand\acro[1]{\textsc{#1}}

\vbadness=1400  % accept slightly empty columns


\let\finalpagebreak\pagebreak % for TUB (if they use it)
\let\finalvspace\vspace       % for document layout fixes

\makeatletter
% maybe not the greatest design but normally we wouldn't have subsubsections
\renewcommand{\subsubsection}{%
   \@startsection {subsubsection}{2}{0pt}{1.5ex \@plus 1ex \@minus .2ex}%
                  {-1em}{\@subheadingfont\colonize}%
}
\providecommand\colonize[1]{#1:}
\makeatother


% Undo ltnews's \verbatim@font with active < and >
\makeatletter
\def\verbatim@font{\normalsize\ttfamily}
\makeatother


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\providecommand\tubcommand[1]{}
\tubcommand{\input{tubltmac}}

\publicationmonth{June}
\publicationyear{2026  --- DRAFT version for upcoming release}

\publicationissue{43}

\begin{document}

\maketitle
{\hyphenpenalty=10000 \exhyphenpenalty=10000 \spaceskip=3.33pt \hbadness=10000
\tableofcontents}



\setlength\rightskip{0pt plus 3em}

\section{Introduction}

% To write

\section{New or improved commands}

\subsection{Recovering instance values}

In some cases, editing template instances requires knowing the existing
instance values. To support this, we have added the expandable command
\cs{InstanceValue}\texttt{\meta{type}\meta{instance}\meta{key}}, which returns
the value if available or otherwise if empty (if the key or instance does not
exist).

\section{Code improvements}

\section{Revision of handling of \enquote{no value} concept}

The commands \cs{NewDocumentCommand}, etc., introduce the idea of
differentiating an absent optional argument from one which is simply empty.
When an argument is entirely empty, it is given the special \enquote{no value}
marker. In previous releases, this was a deliberately-awkward set of character
tokens, which are therefore hard to input accidentally.

Whilst this allowed us to easily detect \enquote{no value}, it turns out there
are places we want to be able to add such a value. This comes up particularly
in creating templates for some parts of the document structure as part of the
wider tagging project.

We have therefore changed the approach to use a marker token, \cs{NoValue}, and
updated the \cs{IfNoValue(TF)} test and relatives. This means you now
\emph{can} type in an optional argument that is interpreted as \enquote{not
present}, but this is not likely to happen by accident.

\section{Bug fixes}

%\subsection{A fix}

%% Some text
%
%%\githubissue{XXXX}



\section{Changes to packages in the \pkg{amsmath} category}

\subsection{Treat \cs{dots} before \cs{xrightarrow} correctly}

If one writes \verb=$ a \to \dots \to b $= the result is $ a \to \dots
\to b $, i.e., \cs{dots} are treated as binary dots. If you replace
\cs{to} with \cs{xrightarrow} then the dots suddenly become comma dots
and you have to use \cs{bdots} to get the binary dots back. This has
now been corrected for both \cs{xrightarrow} and \cs{xleftarrow}.
%
\githubissue{263}

\subsection{Don't lose a qed symbol with \texttt{fleqn}}

The \env{proof} environment of \pkg{amsthm} automatically puts a QED
symbol at the end of a proof.  Sometimes this is not the best place
and in that situation that author can direct \LaTeX{} to place the
symbol earlier by using \cs{qedhere} in an appropriate place. However,
when the \texttt{fleqn} option was in force this didn't always work
and the symbol got dropped in some cases. This has now been corrected.
%
\githubissue{783}



%\section{Changes to packages in the \pkg{graphics} category}

%\section{Changes to packages in the \pkg{tools} category}

%\section{Changes to files in the \pkg{cyrillic} category}

\begin{thebibliography}{9}\frenchspacing

%\fontsize{9.3}{11.3}\selectfont

\bibitem{43:Lamport}
Leslie Lamport.
\newblock \emph{{\LaTeX}: {A} Document Preparation System: User's Guide and Reference
  Manual}.
\newblock \mbox{Addison}-Wesley, Reading, MA, USA, 2nd edition, 1994.
\newblock ISBN 0-201-52983-1.
\newblock Reprinted with corrections in 1996.

\bibitem{43:ltnews} \LaTeX{} Project Team.
  \emph{\LaTeXe{} news 1--42}. November, 2025.
  \url{https://latex-project.org/news/latex2e-news/ltnews.pdf}

\end{thebibliography}

\end{document}

